f\  I  $>. -3:22.4- 


V.  S.  DEPARTMENT   OF   AGRICULTURE 

BUREAU  OF  PLANT  INDUSTRY     BULLETIN  NO.  224. 

B.  T.  OALLOM  IY  Ch   :  0/  Bureau. 


TIMOTHY  HIST  IN  THE  ONITE 


BT 


EDWARP  C.  JOHNSON, 

Pathologist  in  Chargt  o/<  wed  Disease  FPbrifc, 
C^/ft  of  Grain  Investigations. 


Issued  Acocbt  4,  1911. 


"'ORY 


GOVERNMENT    PRINTING    OFFIOE. 

uni. 


U.  S.  DEPARTMENT   OF   AGRICULTURE. 

BUREAU  OF  PLANT  INDUSTRY  -BULLETIN  NO.  224. 

B.  T.  GALLOWAY,  Chief  of  Bureau. 


TIMOTHY  IM  ST  IX  THE  UNITED  STATES. 


BV 


EDWARD  C.  JOHNSON, 

Pathologist  in  Charge  of  Cereal  Disease  Work, 
Office  of  Grain  h 


[8801  D    \>  gcsi   4.  L911. 


^SSSssssSS55 


u  iSHINQTON 

•••■\  I  i;nmi  NT    PRIN  riNl      01 
1911. 


BUREAU    OF    PLANT   INDUSTRY. 


Chief  af  Bureau,  Beverly  T.  Galloway. 
Assistant  Chief  of  Bureau,  William  A.  Taylor. 
Editor,  J.  E.  Rockwell. 
Chief  Clerk,  James  E.  Jones. 


Grain  Investigations. 

scientific  staff. 
Mark  Alfred  Carleton,  Certalist  in  Charge. 
C.  R.  Ball,  Charles  E.  Chambless,  and  II.  B.  Derr,  Agronomists. 
Edward  C.  Johnson,  Pathologist. 

II.  J.  C.  Umberger  and  II.  F.  Blanchard,  Assistant  Agronomists. 
Cecil  Salmon,  Physiologist. 
John  F.  Hoss.  Farm  Supirinlauliiit. 
A.  A.  Potter,  Assistant  Pathologist. 

E.  L.  Adams,  Manley  Champlin,  V.  L.  Cory,  and  II.  V.  Harlan,  Scientific  Assistants. 

F.  R.  liabcock,  Assistant. 

L.  C.  IJurnett,  P.  V.  Cardon,  J.  Mitchell  Jenkins,  Clyde  E.  Leighty,  and  Clyde  McKee,  Agents. 
224 


LETTER  OF  TRANSMITTAL 


U.  S.  Department  of  Agriculture, 

Bureau  of  Plant  Industry, 

<  )i  i  i< ■!•:  of  Chief  of  Bureau, 
Washington,  I>.  C,  May  W,  1911. 
Sir:  I  have  the  honor  to  transmit  herewith  and  to  recommend  for 
publication  as  Bulletin  No.  22 1  of  the  series  of  this  Bureau  the  accom- 
panying manuscript,  entitled  "Timothy  Rusl  in  the  United  States," 
bj  Mi-.  Edward  ('.  Johnson,  of  the  Office  of  drain  Investigations  of 
this  Bureau. 

Timothy  rust,  first  reported  in  the  United  States  in  ivs_\  has 
become  an  important  problem  in  recent  years.  In  L906  it  was  abun- 
dant in  the  timothy-breeding  plats  at  the  Arlington  Experimental 
Farm,  near  Washington,  D.C.  Since  then  it  has  become  widespread, 
causing  considerable  damage  in  many  localities,  and  it-  ultimate  dis- 
tribution over  all  timothy-gro^ ing  regions  \\ here  conditions  arc  fav< ir- 
able  to  rust  development  is  to  he  expected.  This  paper  discussesthe 
present  known  distribution  and  relationships  of  the  rust  of  timothy 
and  summarizes  previous  investigations  of  this  disease  in  Europe  and 
America.  .New  information  on  its  physiological  specialization  and 
methods  of  winter  survival  and  on  the  resistance  of  timothy  strains 
and  varieties  to  rust  is  also  presented. 
Respectfully, 

Wm.  A.  Taylor. 

Acting  t  TiiefofBun  "'/. 
Hon  ,i  wins  Wilson, 

Secretary  ofAgricuUun . 

3 


CONTENTS. 

\  

Pago. 

Distribution  of  the  rust  of  timothy 7 

ption  of  timothy  rusl 8 

Relationship  and  physiological  specialization  of  timothy  ru-t 8 

JScidial  Btage  and  aomenclature  of  timothy  rust H> 

Winter  survival  of  timoth)  rusl L2 

Methods  of  distribution  of  timothy  rust 13 

rieties  of  timothj  to  rust 14 

Summary 16 

Index 19 

224  5 


Digitized  by  the  Internet  Archive 
in  2013 


http://archive.org/details/rustinuniOOunit 


B.  P.  1     I :.' 


TIMOTHY  RUST  IX  THE  UNITED  STATES. 


DISTRIBUTION    OF   THE    RUST    OF   TIMOTHY. 

Rust  of  timothy  was  reported  in  this  country  by  Trelease  as 
c.iH\  as  L882.1  Farlow  and  Seymour,  on  the  basis  of  this  report, 
mentioned  Puccinia  graminis  on  PMeum  pratenst  h.  from  the  I'nited 
States  in  their"  Hosl  In. lex  of  the  Fungi  of  the  United  States"  (1888). 
Rust  of  timothy  was  reported  as  causing  considerable  damage  in  the 
experimental  plats  at  the  Iowa  experiment  station  in  1891. 2  From 
L891  t<>  1906  the  parasite  seems  to  have  been  little  in  evidence 
throughout  the  country,  and  the  writer  has  been  unable  to  find  any 
mention  of  it  during  those  years. 

In  lOOti  the  rust  became  epidemic  in  the  experimental  plats  at  the 
Arlington  Experimental  Farm.  In  1907  it  was  epidemic  at  points  in 
New  York  and  Virginia;  it  was  also  reported  from  Delaware,  West 
Virginia,  and  Ontario,  Canada.  In  1908  this  rusl  was  widespread 
and  caused  much  damage  in  New  York,  Pennsylvania,  Delaware, 
Maryland,  and  Virginia;  it  was  also  reported  from  West  Virginia, 
Ohio,  Michigan.  Wisconsin,  and  Minnesota.  In  1909  the  rusl  was 
common  in  many  of  the  States  mentioned  and  in  addition  was 
reported  from  Indiana,  Kentucky,  Iowa,  and  Maine.  In  1910  it  was 
observed  in  main  States  from  which  it  had  been  previously  reported, 
and  in  considerable  quantity  in  Virginia,  New  York,  Michigan,  and 
Minnesota.  In  the  last  State  it  was  collected  at  both  New  Richland 
and  Owatonna,  and  in  Augu-1  was  exceedingly  abundant  in  timothy 
pastures  around  Crookston.  Thus,  from  being  only  locally  observed 
in  1906,  this  rusl  was  widespread  in  1909  and  L910,  having  been 
reported  from  Maine  to  ( mtario  and  norl  hern  Minnesota,  and  south  to 
Iowa,  Kentucky,  and  Virginia.3 


William.    Parasitic  Fungi  of  Wis  of  the  Wisconsin  Academy  of  Si 

is-:  p.  131.  w  isconsin  was  kindly -ciii  lo  us  for  examination  by  l>r    I 

from  i he  Missouri  Botanical  Gardens.     It  was  rather  unsatl  -  I  of  only  one  rusted 

id  thus  may  have    i  rately  determined,  leavli       i  enticity  of  this 

early  report. 

m,  J., Curtis,  C.  F., and  Kent,  D,  \.     rhni  of  Sowing  Ore  a  Seed.    Bulletin  15,  Iowa  Agricultural 
■  riment  Station,  If 

1  plant  pathol  ious  agricultural  experimi 

!  to  J.  J.  Davis,  M.W.Evans,  I     U    Freeman,  R.  \.  n  irper,  Frank  D.  Kern,  W.J 
Piper,  1 1.  \  .  Yin: 1 11.  II.  l  answered  letters  oi  inquiry  in  regard  to  (lie  rust 

on  timothy  or  have  given  information  us  to  its  prevalence  in  various  localities. 

224 

7 


8  TIMOTHY   RUST   IN    THE    UNITED   STATES. 

DESCRIPTION   OF   TIMOTHY   RUST. 

The  timothy  rust  is  very  similar  in  general  appearance  and  mor- 
phological characteristics  to  Puccinia  graminis  Pers.  on  wheat.  It 
attacks  both  leaf  and  stem,  forming  long,  yellowish-brown  uredo 
pustules  and  dark-brown  to  black  teleuto  pustules,  which  rupture  the 
epidermis.  At  times  it  also  attacks  the  head,  often  preventing  the 
formation  of  seed.  The  uredospores  are  most  prevalent,  while  the 
teleutospores  are  less  abundant. 

The  uredospores  are  18  to  27 p.  in  length  and  15  to  19/*  in  width; 
the  teleutospores,  38  to  52  p.  in  length  and  14  to  16  p  in  width.  This  is 
the  same  range  as  that  of  the  corresponding  spores  of  Puccinia 
graminis  Pers.  on  wheat,  but  the  variation  is  not  quite  as  great  as  in 
the  wheat  rust.  The  teleutospores  are  constricted  in  the  middle  and 
have  a  much  thickened,  round  or  pointed  apex  and  pedicels  of 
medium  length,  and  closely  resemble  those  of  the  typical  Puccinia 
graminis  Pers. 

RELATIONSHIP     AND     PHYSIOLOGICAL     SPECIALIZATION     OF 

TIMOTHY  RUST. 

In  1908  and  1909  inoculation  experiments  on  various  grasses  were 
undertaken  at  Washington,  D.  C,  to  determine  the  relationship  of 
the  rust  of  timothy  to  rusts  of  other  hosts  in  this  country  and  to 
ascertain  whether  or  not  it  is  the  same  form  as  that  which  occurs  in 
Europe.  Collections  were  made  at  the  Arlington  Experimental 
Farm,  and  fresh  material  in  the  uredo  stage  was  kept  growing  in  the 
greenhouses  at  Washington,  D.  C.  All  inoculations  were  made  on 
young,  fresh  leaves  of  the  host  plants  growing  in  pots.  The  plants 
were  kept  moist  for  48  hours  after  inoculation  by  placing  the  pots  in 
moist  chambers  consisting  of  large  bell  jars  placed  in  pans  containing 
sand  and  a  little  water.  In  this  way  a  thin  film  of  water  soon  con- 
densed on  the  leaves  and  remained  as  long  as  the  plants  were  covered. 
This  gave  ideal  conditions  for  spore  germination  and  for  infection. 
The  results  of  these  inoculations  are  reported  in  Table  I. 

224 


RELATIONSHIP    \M>    PHYSIOLOGICAL  SPECIALIZATION.  9 

!  inoculati  (h  uredosj   ■ 


1  Inocu 
latlon. 

Source  of  Inoculating 
material. 

Varieties  of  plants  Inoculated. 

Number 
of  leaves 

lated. 

Number 
of  suc- 
cessful 
infei- 

during 
Incuba- 

rind  of 
17  to  21 
days. 

1 

Jan,    2 
Jan.    25,1908 

Phleum  pra tense. . . 

Tritlcum  vulgare 

1 

■> 

i 

;j 

in                i 

1 

in 

A  vena  sativa 

10                    ' 

5 

Jan. 

Feb. 
Feb. 

1  .n.    i 

Feb.  ! 

Feb. 

Jan.    27,1909 

1.1909 
.do 



23 
25 
5 
3(j 
24 
42 
22 
i  25 
16 

18 
18 
3 
18 

1 
33 

■ 

Id 
25 
9 
Hi 
11 
21 
17 
28 
44 
31 
11 

40 
7 

11 

i 

. 

.    . .  .do 

s 

1 

'1 

10 

t 

11 

C 

12 



i 

1 

13 



1 

1 1 

i 

i 

...do 

Vrrhenatherum  elatius 

.   .do 

0 

17 

ti 

18 

..do... 

2 

19 

.do. 



( 

...do... 

.do 

7 

21 

0 

22 

Feb.     . 

Jan.   27. 1909 

Jan.    23  1909 

Feb.  •.' 
.do 



( 

...do 

...do 

i 

L'l 

.do.   . 

.do... 

0 

25 

do 

0 

26 

0 

"7 

do 

do 

...do 



0 

28 

ntale 

Ilnrdcuiu  jubatum 

0 
0 

Mar. 

.do.. 

0 

31 

• 

0 

32 

1     !.. 

1    | 

Jan.   2 

Jan.    2 

I  v  hvstrix 

0 

;  : 

.do.. 

0 

...do 

do 

0 

lo 

do 

0 

do 

0 

The  rusl  rather  easily  transferred  to  Avena  sativa  (17  out  of  30 
inoculations)',  Secah  cereah  (8  out  of  11  inoculations),  Festuca 
<l<i!'iorl  (6  out  of  66  inoculations),  Dactylis  glomerata  (22  out  of  122 
inoculations),  Arrhenatherum  elatius  (8  out  of  47  inoculations),  am! 
/'..</  compressa  (13  out  of  17  inoculations),  [noculations  on  other 
grasses  produced  no  infection.  Similar  results  were  obtained  1>\ 
Eriksson3  in  inoculation  experiments  with  this  rust  on  Avena  sativa, 
Secah  cereale,  and  Festuca  elatior?  No  inoculations  on  Dactylis 
glomerata,  Arrhenatlierum  elatius,  or  Poa  compressa  arc  cited  in  his 
report.  Direct  inoculation  on  Trvticum  vulgare  and  Hordeum  vulgurt 
gave  negative  results  in  10  trials  each,  thus  corresponding  to  the 
negative  results  in  numerous  siniilar  trials  of  Eriksson.3     From  these 

n  our  work.    It  Is  probable  that  was  used  bj  Eriks- 

son, as  this  is  the  common  form  known  by  that  name  in  Sweden. 
•  Eriksson,  Jakob.    1st  der Tlmothei  elneselbst&i  rtodernicht?    Sfversigt  af  Ron 

.  Vetenskaps-Akademiens  Forhandlingar,  no.  .s,  1902,  pp.  193-190. 

92430      Bui   224   -11 2 


10  TIMOTHY   RUST   IN    THE   UNITED    STATES. 

experiments  it  may  be  concluded  that  the  rust  in  the  United  States 
and  the  rust  in  Europe  are  identical,  and  the  statement  by  Eriksson  ' 
that  it  is  not  a  well-fixed  species  is  substantiated.  Although  timothy 
rust  can  easily  be  transferred  to  Avena  sativa,  Eriksson  '  and  Carle- 
ton  2  have  shown  that  the  uredo  of  Puccinia  graminis  avenae  Erikss. 
and  Ilenn.  can  not  be  made  to  grow  on  timothy.  This  rust,  however, 
can  easily  be  transferred  to  Dactylis  glomerata  and  Arrhetiatherum 
elatius.2  Timothy  rust  also  transfers  to  these  hosts  (Table  I).  These 
rusts,  therefore,  although  not  identical,  have  many  characteristics  in 
common,  which  indicates  that  there  probably  is  a  very  close  relation- 
ship between  the  two. 

A  small  number  of  experiments  to  test  whether  or  not  the  timothy 
rust  can  be  transferred  by  means  of  bridging  hosts  to  various  cereals 
which  are  not  successfully  infected  directly  from  timothy  were  tried 
and  it  was  found  that  by  using  Avena  sativa  as  a  bridging  host  the 
rust  easily  transferred  to  Hordeum  vulgare  (4  times  in  10  trials);  by 
using  Festuca  elatior  it  transferred  to  Hordeum  vulgare  (twice  in  10 
trials)  and  to  Triticum  vulgare  (once  in  10  trials);  and  by  using 
Dactylis  glomerata,  it  transferred  to  Triticum,  vulgare  (once  in  5  trials). 
By  the  use  of  the  bridging  hosts  the  rust  undoubtedly  could  be  made 
to  transfer  to  many  grasses  on  which  it  will  not  grow  when  coining 
directly-  from  timothy,  but  on  which  it  might  continue  to  grow  after 
such  a,  transfer.  That  this  to  some  extent  takes  place  in  nature  is 
very  probable,  and  these  trials,  together  with  recent  experiments  of  a 
similar  nature  on  the  rusts  of  grains,3  throw  much  light  on  the  pos- 
sible origin  of  many  of  the  so-called  "physiological  species"  of  rust. 

ffiCIDIAL  STAGE  AND  NOMENCLATURE  OF  TIMOTHY  RUST. 

The  secidial  stage  of  the  rust  is  not  definitely  known.  Eriksson 
and  Henning  4  noticed  that  the  timothy  in  the  neighborhood  of  bar- 
berries was  not  affected,  while  other  grasses  in  the  same  locality  were 
rusted.  In  two  trials  in  1801  they,  were  unable  to  secure  infection 
on  timothy  with  secidiospores  from  Berberis  vulgaris.  In  1892-3 
aecidia  on  Berberis  vulgaris  were  obtained  by  them  after  inoculation 
with  teleutospores  of  timothy  rust  once  in  nine  trials,  and  that  in  only 
one  place  of  inoculation  against  !»2  places  inoculated  with  negative 
results.  This  one  positive  result  may  have  been  due  to  accidental 
infection  from  some  other  source,  as  two  leaves  on  the  same  hush 

i  Loc.  oil.. 

ii  leton,  Mark  Alfred.    Cereal  Rusts  of  the  Unite,  i  suites.     Bulletin  16,  Division  of  Vegetable  Physlot 

iinl  Pathology,  U.S.  Dept.  ol  Agriculture,  1899,  pp.  61-62. 

reeman,  E.  M..  and  Jofinson,  Edward  C.    1  he  Rusts  ol  Orals  in  the  United  States.    Bulletin  216, 

I in  if  Plant  Endustry,  V.  s.  Dept.  of  Agriculture,  1911,  p.  16. 

■  Eriksson,  Jakob,  and  Henning,  Ernst.    l>ie  Haupt-Resultate  einei  ueuen  Untersuchung  fiber  die 
Oetreideroste     Zeitschrifl  fiir  Pflanzenlcrankhelten,  vol.  •>.  1894,  p.  140. 
224 


iECIMAl.    BTAGE     \NI>    NOMENCLATURE.  11 

which  had  not  been  artificially  inoculated  also  produced  secidia.1  In 
L895  Eriksson  again  made  inoculation  experiments  on  the  barberry 
with  the  teleutospores  of  this  rust,  bul  in  25  inoculations  none  was 
successful.2  In  this  couni  r\  Kern3  in  L  908  observed  eight  unsuccessful 
inoculations  on  I  he  barberrj . 

From  their  results  Eriksson  and  Henning  concluded  thai  timothy 
rusl  ■!<>«'-;  in ■  t  form  its  secidial  stage  on   tin-  barberry,  while  Kern3 
says  1 1  in  i  "'Im'  one  positive  result  mentioned  ought,  it  seems,  [to]  bo 
accorded  more  weighl  than  all  the  negative  ones  together,  and  pro-*  < 
thai    it    [timothy  rust]   does,  even   if  with  difficulty,  form  its 
stage  upon  the  barberry."     Eriksson  an. I  Henning  regard  the  rusl 
a  distinct  species  and  name  it   Puccinia  phlei-pratensis,  while  Kern 
considers  it  "a  race  of  Puccinia  poculifoi  •  •  •!■  a  so-called 

physiological  species."  Evans  accepts  the  name  Puccinia  phlei- 
pnili  nsis,*  and  in  a  discussion  of  t  lie  development  of  the  uredo  my  eel  i  a 
of  the  cereal  rusts  shows  that  there  are  differences  in  the  details  of 
infection  of  this  rusl  and  Uredo  graminis,  which,  although  slight,  are 
well  marked.  In  a  later  paper  Kern  states  that  he  is  still  of  the 
opinion  that  this  rusl  is  nol  entitled  to  specific  rank  and  would 
include  it  under  ''Puccinia  poculiformis  (Jacq.  Wettst.,"  i.  c..  Puc- 
cinia graminis  Pers.  Me  modifies  his  previous  statement  as  to  its 
being  a  physiological  species  and  thinks  it  mighl  better  be  considered 
a  variety  or  subspecies,  •'since  it  does,  as  previousl}  pointed  out. 
possess  some  slight  morphological  differences  from  the  typical  form. 
particularly  in  the  smaller  recial  cups  and  the  more  delicate  uredinial 
mycelium." 

From  the  physiological  specialization  of  this  rust,  as  shown  in 
experiments  above  reported:  from  it<  distinctive  method  of  infection 
from  the  uredospore,  as  described  i>\  Evans;  from  the  difficulty  with 
which  it  produces  its  secidium  on  barberries,  as  shown  by  Eriksson 
and  Henning;  and  from  the  delicacy  of  ilu-  mycelium  of  the  uredo 
stage  a-  compared  with  the  typical  graminis  form,  as  cited  by  I. 
it  i-  evident  that  the  rust  of  timothy  has  many  distinctive  character- 
istics, and,  even  if  not  well  fixed,  is  highly  specialized.  Whether  or 
not  it  should  he  regarded  as  a  distinct  species  is,  perhaps,  debatal  I. 

i  Eriksson,  Jakob,  and  Henning,  Ernst.    DIo  Gob  i:s7. 

:  Kriksson.  Jakob,     l  i   der    PI  <.»rt  oder  nicht?    Ofversigt  af 

191. 
i     '              I         ■    i  Lmothj .     ["on                 I  <   ■   i  i        09,  p.  4 
>  Evan  ,I.B.  Pol  of!  hell  Un                                 ol  Botany, 
vol.21,  i                                       "  The  sub  >sely  re- 
sembling that  of  Uredo  graminis,  but  narrower    *   *   *.  It  differs  from  Uredo  graminis  chiefly  in  1 
thai  the  end  from  which  thehypha  Bprln  of  the  guard  cell." 
i,  K.  l>.    Further  Notes  on  Timothy  Rust.     Pro  Indiana  Acad 

224 


12 


TIMOTHY    RUST   IN    THE    UNITED    STATES. 


Some  method  <>t:  differentiating  this  rust  in  literature  from  the  com- 
mon gramlnls  forms  is  necessary,  however,  and  unless  further  experi- 
ments should  show  that  it  can  produce  its  avidium  on  the  barberry, 
and  until  such  experiments  have  been  performed,  the  writer  favors 
the  use  of  the  specific  name  Puccinia  flilei-'pratensis  Erikss.  and  Henn. 


WINTER    SURVIVAL   OF   TIMOTHY   RUST. 

In  1908  an  effort  was  made  to  determine  how  the  rust  survives  the 
winter  at  the  Arlington  Experimental  Farm.  Timothy  plants  were 
removed  from  the  field  on  January  19  and  March  12  and  were  imme- 
diately potted  and  placed  in  a  greenhouse  at  Washington,  D.  C,  where 
they  could  be  carefully  watched  and  any  further  development  of  rust 
noted.     Table  II  shows  the  results  of  these  experiments. 

Table  II. — Results  of  experiments  on  the  wintei  survival  of  the  rust  of  timothy. 


Observations 

Serial 

Placed 

No. 

in  green- 

house. 

Date. 

Result. 

Date. 

Result. 

Date. 

Result. 

1908. 

1908. 

1908. 

1908. 

1 

Jan.    _'ii 

Jan.    22 

Pour    unopened 
pustules   near 
tip  of  one  leaf, 
several    flecks 
in  center. 

Jan.   28 

Pustules  near  tip 
not  open,   three 
fresh  open  pus- 
tules at  center 
where  flecks  oc- 
curred. 

Feb.     3 

Endofleaf  dried, 
numerous  fresh 
pustules  over 
remainder  -o( 
leaf. 

2 

...do 

...do.... 

No     rust     pus- 
tules, no  flecks. 

...do.... 

...do 

No  rust. 

3 

...do 

...do 

Seven  unopened 
pustules       on 

...do 

Several  fresh  open 
pustules     on 
both  sides    of 

...do 

Leaf  covered 
\vi  th  vigorous 

upper  side  of 

pustules. 

one  leaf,  sev- 

leaf,    several 

eral  on  lower. 

new  pustules. 

4 

...do 

...do 

Six    pustules 
near  tip  on  up- 
per side  of  one 
leaf,    six     on 

...do 

Six    pustules    on 
upper    side    of 

...do.... 

New  pustules 
still     forming, 

leaf,      six      on 

old  ones  vigor- 

lower near  tip, 

ously    produc- 

lower. 

vigorous;    three 
fresh     pustules 
on   upper  side: 
three   on   lower 
near  center,  two 
of  them  open. 

ing  spores. 

5 

do  .  .  . 

...do 

One  pustule  on 
middle  of  up- 

...do  

Leaf  drying 

...do 

Leaf        almost 

dead,  no    new 

per  side  of  one 
leaf,        leaf 

pustules. 

partly  dried. 

6 

Mar.   13 

Mar.  13 

Several  pustules 

at  base  of  one 
leaf. 

Mar.    19 

No     further     de- 
velopment      of 

rust. 

Mar.  25 

No  further  de- 
velopment   of 

rust. 

7 

...do.... 

...do.... 

Unopened    pus- 
tules at  base  of 

...do 

Three  fresh   pus- 
tules   on     leaf; 

...do 

Three  fresh  pus- 
tules   on    leaf, 

cine  leaf,  other 

more  than  2  per 

and        several 

leaves  flecked. 

cent      of      the 

fresh  pustules 
on         leaves 

spores      from 
these     pustules 

which     were 

• 

germinated     in 
water. 

flecked. 

8 

...do 

..  do  ... 

Unopened    pus- 
tules on  many 

...do 

Two    open    pus- 

...do  

Fresh  open  pus- 

tules    on     one 

tules  on  many 

leaves. 

leaf. 

leaves. 

9 

...do 

...do.... 

One  pustule  on 
each    side    of 

...do 

No     further     de- 

...do  

No    further    de- 

velopment      of 

velopment     of 

one  leaf  near 
tip. 

Leaves  with  sev- 

rust. 

rust. 

io   ...do 

...do 

...do 

do 

...do 

Do. 

eral  unopened 

pustules. 

224 


METHODS    OF    DISTRIBUTION.  13 

It  is  soon  that  some  of  the  plants  broughl  in  on  January  19  and 
March  12,  notably  Nos.  1,  3,  4,  7,  and  8,  continued  to  produce  uredo- 
spores.  At  Arlington,  in  1908,  fresh  rusl  pustules  on  new  growth 
of  timothy  were  common  after  March  L5.  Undoubtedly  the  old 
rust  mycelium  living  in  the  plants  had  produced  these  pustules. 
Spores  collected  on  January  20  and  March  13,  1908,  were  found  to 
be  viable. 

Similar  conditions  undoubtedly  prevail  in  other  localities  of  the 
same  latitude  and  similar  climate  where  this  rust  is  found.  How 
the  rust  winters  farther  north  has  not  been  determined,  hut  in  the 
light  of  recent  investigations  '  it  is  very  probable  that  it  lives  through 
the  winter  in  the  uredo  stage  much  farther  north  than  the  latitude 
cited.  As  shown  by  specimens  sent  to  the  Office  of  Grain  Investi- 
gations, it  seems  that  teleutospores  of  this  rust  are  more  abundant 
m  northern  latitudes  than  at  the  Arlington  Experimental  Farm, 
where  they  were  very  scarce  in  lt»i>7  and  190S.  At  the  latter  place 
the  parasite  Darluca filv/m  (Biv.)  Cast,  largely  prevents  the  forma- 
tion of  the  teleuto  stage,  as  almost  every  pustule  ready  to  produce 
teleutospores  is  attacked  by  this  fungus  and  further  development 
is  prevented.  However,  as  the  secidial  stage,  if  present,  is  undoubt- 
edly rare  in  this  country,  the  teleuto  stage  is  o'i  doubtful  importance 
in  the  wintering  and  dissemination  of  the  rust. 

METHODS   OF    DISTRIBUTION   OF  TIMOTHY   RUST. 

The  rapid  distribution  of  timothy  rust  in  recent  years  is  doubtless 
due  to  the  dissemination  of  the  uredospore  by  the  usual  agencies. 
Insects  have  been  shown  to  be  carriers  of  spores,  birds  and  other 
animals  may  carry  them  from  place  to  place,  they  maj  be  transferred 
from  one  region  to  another  by  man  through  the  shipment  of  rusted 
timothy  hay.  etc.,  but  most  important  is  the  agency  of  the  wind. 
It  lias  been  shown  probable3  that  the  uredospores  of  rusts  are  dis- 
tributed by  the  wind  Dol  only  from  field  to  held,  but,  rising  into  the 
upper  air,  are  carried  by  currents  for  hundreds  of  miles.  With  a 
quantity  of  uredospores  on  hand  in  various  localities  early  in  the 
spring,  their  distribution  thus  becomes  an  easy  matter  and  the 
general  dissemination  of  rusl  over  large  areas  is  accounted  for. 
Undoubtedly,  in  the  course  of  a  few  years,  the  distribution  of  I 
rust  is  to  he  expected  over  all  timothy-growing  sections  where  con- 
ditions are  favorable  for  its  development. 

With  the  ultimate  dissemination  of  rusl  over  the  greater  part  of 
the  timothy  area  a  practical  certainty,  methods  of  preventing  any 

1  Freeman  ;it>'l  Johnson,  loo  <  ii . 

■Johnson,  Edward  C      I  s  In  the  Southwest.    Phytopathology,  vol  1, 1911,  p.  18. 

•  Freeman  and  Johnson,  loc.olt.;  and  EClebahn,  it..  Die  wirtsweohselnden  RostpUxe,  1904,  pp. 

....  j 


14  TIMOTHY    RUST    IN    THE    UNITED   STATES. 

considerable  damage  to  the  timothy  crop  from  this  parasite  become 
necessary.  Only  one  method  at  present  known  can  be  employed 
against  it  with  any  promise  of  success,  and  that  is  the  development 
of  varieties  of  timothy  resistant  to  rust.  To  this  end  work  has 
been  commenced. 

RESISTANCE   OF   VARIETIES   OF  TIMOTHY  TO   RUST. 

A  fair  opportunity  was  offered  to  study  the  resistance  of  varie- 
ties of  timothy  to  rust  and  to  make  selections  for  rust  resistance  at 
the  Arlington  Experimental  Farm  during  1908  and  1909,  as  the 
disease  was  plentiful  in  those  years.  Mr.  W.  J.  Morse,  of  the  Office 
of  Forage-Crop  Investigations,  who  had  charge  of  timothy-breeding 
work  at  that  place,  says  in  an  unpublished  report : 

By  July  30  (1908)  no  tirnothies  were  found  to  be  entirely  free  from  rust.  *  *  * 
The  rust,  resistance  varied  greatly,  ranging  from  zero  to  98  per  cent .  In  some  instances 
a  few  small  rust  spots  appeared  on  the  culms  and  no  rust  on  the  leaves.  Several  selec- 
tions made  no  growth  at  all,  the  rust  appearing  to  stunt  the  growth.  In  other 
instances  the  plants  made  some  growth,  but  the  production  of  seed  was  prevented. 
In  1909  the  rust  attack  at  the  Arlington  Experimental  Farm  was  even  more  severe 
than  in  1908,  although  the  rust  did  not  appear  to  any  extent  until  the  middle  of  May. 
This  severe  attack  brought  to  light  the  fact  that  many  of  the  strains  marked  "resist- 
ant" in  1908  appeared  to  be  much  less  resistant  in  1909.  It  was  noticeable,  however, 
that  the  relative  resistance  of  the  different  strains  was  very  little  different  in  1909 
from  what  it  was  in  1908. 

In  1910  the  rust  attack  on  the  same  farm  was  not  nearly  so  severe 
as  in  the  two  preceding  years.  Under  such  conditions  the  distinc- 
tion between  resistant  and  nonresistant  strains  is  not  nearly  as  well 
marked  as  when  rusts  are  abundant.  As  a  result  many  strains 
failed  to  retain  in  their  resistance  percentages  the  same  relative  posi- 
tion Avhich  they  occupied  in  1908  and  1909.  This  corroborates  the 
experience  of  the  writer  that  the  value  of  rust-resistance  figures 
obtained  in  years  when  the  rust  is  not  abundant  or  at  places  where 
the  rust  attacks  are  not  severe  is  questionable  and  shows  that  the 
notes  taken  at  such  times  and  places  may  often  be  misleading. 
Dependable  data  can  be  secured  only  either  in  "rust  years"  or 
in  places  where  vigorous  rust  attacks  occur  or  are  artificially  pro- 
duced every  year.1 

In  order  to  determine  whether  or  not  the  figures  on  rust  resist- 
ance obtained  in  the  field  during  seasons  when  rust  is  abundant  are 
comparable  to  data  secured  where  different  strains  are  placed  under 
identical  conditions  and  subjected  to  artificial  inoculation,  experi- 
ments were  undertaken  in  1909  in  the  greenhouses  at  Washington, 
D.  C.  Seed  of  various  strains  of  timothies  from  the  1908  selections 
at  the  Arlington  Experimental    Farm  was  planted  in  4-inch  pots. 

'  Freeman  and  Johnson,  loc.  cit. 
224 


RESISTANCE    OF    VARIETIES    OF    TIMOTHY. 


15 


When  the  timothy  was  aboul  _'  inches  high,  it  was  thinned  to  It) 
plants  or  less  in  a  pol  and  the  ! i i--> t  leaf  of  each  plant  was  inoculated 
by  placing  on  it.  by  means  of  a  flattened  inoculating  needle,  a  small 
quantity  of  fresh  uredospores.  The  pots  were  placed  in  a  moist 
chamber  for    '•  as  described   on   pairc  s  of  this  paper,  ami 

were  then  removed  and  allowed  to  stand  for  17  to  21  days,  when 
final  notes  were  taken.  The  percentage  of  noninfection  from  uredo- 
spore  inoculations  of  timothy  selections  and  the  rust-resistance 
percentages  of  these  -elections  in  the  field  during  L908  and  1909 
are  shown  in  Table  1  If. 


Table  111.   -Tht   percen  om  uredospore  inoculations  of  timothy 

selections  and  th<  ru  percentages  of  thesi  selections  in  the  field  during  1908 

and  1909. 


Serial 

1  >  ite  of  Inoculation. 

Timothy 
tions. 

inocu- 

Scuba"- 

not  in- 
fected. 

ince  in  field. 

1909 

1 

1909. 
2  

i 
29   \ 

IS    1! 

52  B 

1 
K 

16 

19 

7.".  C 

15    \ 

:(7    \ 
19    \ 

2s 
is 
12 
19 
5 
11 
11 
O 
11 
Hi 
14 
8 
8 

7 

is 
17 
19 

■ 

11 
is 
11 

8 

Nitmber. 

Id                  17 
4                  17 
6                 17 

I'ir  cult. 
64 

77 

Per  cud. 

98 

80 

0 

CO 

70 

60 

98 

90 

0 

0 

OS 

50 

2 

30 

3 

.do 

(') 

4 

do       

12                 17                 :(7 

17 
6                    is                   40 
1                     Is                    71 

5 

20 

6 

7 



s 

...do 

IS 
1 

- 

13                is 

.'1 
21 
11 

:«; 
91 
19 

7 
0 

9 

.do  

10 

11 

in 

12 



40 

13 

do  

0 

it;             on 

40 

1 1 

15 

21                 25                70 

6  21                 11                  0 
15                21                 17                98 
17                                     0                  0 

1.-,                  21                  21 

21                    0                 60 

21                  is 
12                 21                  34                  77, 

7  is                 50 
3                  is 

16 

17 

do 

40 

In 

....do. .. 

(') 

20 

.  ...do 

10 

7<l 

21 



do 

in 

22 

23 

j.i  .   . 

20 

irded. 

The  percentages  of  inoculated  leaves  winch  did  not  develop  rust  do 
nut  correspond  with  the  rust-resistance  figures  obtained  in  the  held. 
This  i-  accounted  lor  by  the  fact  that  even  the  most  rust-resistant" 
Varieties  of  both  uri'a>scs  and  cereals  will  develop  rusl  to  some  extent 
when  carefully  inoculated  in  the  greenhouse  with  the  rust  most  com- 
mon on  the  respective  hosts.  It  is  always  noticeable,  however,  that 
although  every  inoculated  leaf  of  a  rust-resistanl  strain  may  he 
affected,  the  rusl  infei  tion  is  much  less  severe  on  them  than  on  sus- 
ceptible varieties.  Therefore  in  making  observations  on  rust  resist- 
ance not  only  the  percentage  of  leaves  developing  rust  pustules  hut 
also  the  severitj  of  the  infection  must  he  considered.  Although  such 
observations  arc  not  noted  in  Table  III  il  was  found  that ,  in  so  far  as 

22  1 


16  TIMOTHY   RUST    IN    THE    UNITED    STATES. 

the  vigor  of  the  infection  was  concerned,  the  relative  rust  resistance 
of  strains  as  obtained  in  the  field  was  fairly  well  maintained  in  the 
greenhouse  experiments  and  that  the  differences  in  resistant  and  sus- 
ceptible strains  were  marked. 

Having  determined,  then,  that  there  are  wide  differences  in  timothy 
strains  with  regard  to  resistance  and  susceptibility  to  rust,  the  prob- 
lem in  timothy-rust  prevention  is  one  of  breeding.  This  may  not  be 
as  difficult  as  it  appears  at  first,  since  up  to  the  present  time  timo- 
thies  have  not  been  highly  bred  and  there  are  not  only  great  differ- 
ences between  varieties  but  apparently  unusual  variations  within  a 
variety.  Response  to  selection,  therefore,  may  be  both  rapid  and 
well  marked.  Such  breeding,  however,  to  be  of  any  value  must  be 
carried  on  in  places  where  the  rust  is  abundant  or  where  either  natur- 
ally or  artificially  a  rust  attack  occurs  every  year. 

SUMMARY. 

Timothy  rust  was  reported  in  the  United  States  as  early  as  1882. 
It  was  reported  from  Iowa  in  1891.  From  1891  to  1906  no  men- 
tion of  the  parasite  has  been  found.  In  1906  the  rust  became  epi- 
demic at  the  Arlington  Experimental  Farm,  near  Washington,  D.  C, 
and  since  then  has  been  found  to  be  widespread,  having  been  reported 
from  Maine  to  Ontario  and  northern  Minnesota  and  south  to  Iowa, 
Kentucky,  and  Virginia. 

Timothy  rust  is  similar  in  general  appearance  and  morphological 
characteristics  to  Puccinia  graminis  Pers.  on  wheat. 

Inoculation  experiments  with  timothy  rust  at  Washington,  D.  C, 
show  that  it  can  be  transferred  easily  to  various  grasses.  Similar 
results  have  been  obtained  by  Eriksson  in  Europe.  This  demonstrates 
that  the  rust  in  the  United  States  and  the  rust  in  Europe  are  identical. 
That  it  is  not  a  well-fixed  species  is  substantiated.  By  using  bridging 
hosts  timothy  rust  can  be  made  to  transfer  to  various  cereals  which 
it  will  not  attack  directly.  That  such  transfers  take  place  in  nature 
to  some  extent  is  probable. 

The  a?cidial  stage  of  this  rust  is  not  definitely  known.  Eriksson  and 
Henning  in  numerous  inoculations  with  the  teleutospores  on  bar- 
berries obtained  negative  results  except  in  one  instance.  On  this 
basis  they  consider  the  rust  a  distinct  species,  naming  it  Puccinia 
phlei-pratensis.  Kern  has  observed  several  unsuccessful  inoculations 
on  the  barberry  in  this  country.  From  the  one  apparently  positive 
result  of  Eriksson  and  Henning,  however,  he  believes  that  the  rust  is 
not  entitled  to  specific  rank  and  should  be  included  under  Puccinia 
graminis  Pers.  Evans  accepts  the  name  Puccinia  pMei-pratensis  and 
shows  that  there  are  well-marked  differences  in  the  details  of  the 
infection  from  the  uredospore  of  tliis  rust  and  the  graminis  form  on 

224 


SUMMARY.  17 

cereals.  From  the  physiological  specialization  of  the  rust,  from  its 
distinct  method  of  uredospore  infection,  from  the  numerous  negative 
results  of  inoculations  with  the  teleutospore  on  barberries,  and  from 
the  delicacy  of  i  he  uredo  m\  celium,  as  compared  wit  li  t  \  pica]  gramin  Is 
forms,  it  is  evident  that  this  rust  has  many  distinctive  characteristics. 
Unless  further  experiments  should  showthal  the  rusl  can  produce  its 
recidium  on  the  barberry  and  until  such  experiment  have  been  per- 
formed, the  writer  favors  the  use  of  the  specific  name  Pucdnia  pMt  i- 
pratt  nsis  Erikss.  and  I  [enn. 

At  the  Arlington  Experimental  Farm  the  rust.mycehum  lives 
through  the  winter.  It  is  very  probable  that  it  lives  over  winter  in 
the  uredo  stage  much  farther  north  than  the  latitude  cited.  As  the 
SBcidial  stage,  it'  present,  is  undoubtedly  rare  in  the  United  State  the 
teleuto  stage  is  of  doubtful  importance  in  the  wintering  and  dis- 
seminat  ion  of  t  he  i  ust. 

The  rapid  distribution  of  timothy  rust  in  recenl  years  is  undoubt- 
edly due  to  the  dissemination  of  the  uredospores  l>\  the  usual  agencies, 
namely,  insects,  birds,  animals,  man.  surface  winds,  and  upper  air' 
currents.  Its  ultimate  distribution  over  all  timothy-growing  sec- 
tions favorable  to  it  is  to  he  expected,  and  methods  of  preventing 
any  considerable  damage  to  the  timothy  crop  become  necessary. 

In  a  study  of  the  resistance  of  varieties  of  timothy  to  rust  in  1908 
and  1909,  W.  J.  Morse  found  that  the  resistance  "varied  greatly, 
ranging  from  zero  to  98  percent."  The  resistance  of  differenl  strains 
relative  to  each  other  varied  little  during  the  two  years.  Under  a  less 
severe  rust  attack  in  L910  these  strains  in  many  instances  failed  to 
retain  the  same  relative  position  as  in  previous  years.  Tin--  lends  to 
show  that  dependable  data  can  he  obtained  only  when  vigorous  rust 
attacks  occur. 

In  greenhouse  experiments  where  strains  which  had  been  tested  in 
the  held  were  subjected  to  similar  inoculation  and  identical  condi- 
tions during  the  period  of  incubation,  the  percentage  of  inoculated 
leaves  which  did  not  become  infected  did  not  correspond  with  I  lie 
figures  on  rust  resistance  obtained  in  the  field.  When  the  severity 
of  infection  and  not  the  percentage  of  leaves  developing  pustules  was 
considered,  however,  the  relative  resistance  of  strains  as  obtained  in 
the  field  was  fairly  well  maintained  in  the  greenhouse. 

A  -  t  here  are  wide  differences  in  timothy  strains  with  regard  to  rusl 
resistance,  the  problem  in  t  imot  li\  -rust  prevention  become-  one  of 
breeding.  This  maj  qoI  be  as  difficult  as  it  appears  at  first.  Such 
work,  however,  to  be  of  value  must  be  carried  on  when  the  rust  is 
abundant  and  where  either  naturally  or  artificially  a  rust  attack 
occurs  every  year. 
..I 


INDEX. 

Page. 

id(  Mai.-  host  of  timothy  rust 9 

iosI  of  timothy  rust 9 

Airhenatherum  i              lostof  timothy  rusl 9, 10 

A. vena  Eativa,  bosl  of  timothy  rust 9,  L0 

Barberry,  attempts  at  inoculation  with  timothy  rust 10-11,  12,  16  17 

Berberis  \  ul  .in       Set  Bai  berry. 

Funis,  agency  in  the  ili--ciniyuuii.il  of  rust  spores 13, 17 

Breeding,  rust-resistant  varieties,  methods I  I   17 

Bromus  unioloide  .  I  ost  of  timothy  rust 9 

i  larleton,  M     \  .  on  host  plants  of  grain  rusts 10 

(urn-,  c.  !•'.,  Wilson,  J.,  and  Kent,  1>.  A  ,  on  the  occurrence  of  timothy  rust . .  7 

Dactylis  g] rata,  host  of  timothy  rust 9,  10 

Darluca  Slum,  parasite  of  timothy  rust 13 

111 yimis  spp.,  Iii i- 1-  "i  timothy  rusl 9 

Eriksson,  Jakob,  and  Eenning,  Ernst,  on  experiments  with  timothy  rust 10,  1 1 

■  ■11  inoculation  experiments  with  timothy  rust 9,  10,  II 

Evans,  1    B    P.,  on  investigal  ions  of  rusts II 

Experiments,  inoculation,  with  timothy  rusl 8  10, 14   17 

Farlow,  W,  G  .  and  Seymour,  A.  B.,  on  the  rust  of  timothy i 

Fescue,  tall  meadow,  use  in  inoculation  i  cperiments  with  i inn ithy  rust 9 

Festuca  elatdor,  host  of  timothy  rust 9,  10 

Freeman,  E.M.,  and  John  on,  E  '    ,  on  the  rusts  of  grain  in  the  United  States.  10,13,14 

Benning,  Ernst,  and  Eriksson,  Jakob,  on  experiments  with  timothy  rust 10 

Bolcus  ianatus,  host  of  timothy  rusl 9 

Bordeum  Bpp  .  boste  of  timothy  rust 9, 10 

Bo  i .  bridging,  use  in  transfer  of  nu  1 10,  16 

Bystrix  hystrix,  host  of  timothy  rust 9 

Inoculation  experiments.     Sa  Experiments,  inoculation. 

Insects,  agency  in  the  dissemination  of  rust  spores 13,  17 

Johnson,  E.  C.,and  Freeman  E.M.,  on  the  rusts  of  grain  in  the  United  States.   L0, 13, 14 

on  the  dissemination  of  rusl  Bpores 13 

Kent,  D.  A.,  Wilson,  J.,  and  t  urtis,  <  .  F.,  on  the  occurrence  of  timothj  rust.  7 

Kern,  F.  D  ,  on  the  rust  of  timothy II 

Morse,  W.  J.,  on  rust  resistance  of  timothy 14, 17 

Phalarie  arundinacea,  ho  i  of  timothy  rust 9 

Phleum  pratense,  host  of  timothy  rust 7.  9 

Poa  Bpp  .                  mothy  rusl 9 

I'm  ri ma  graminis,  occurrence  on  stated  host  plants 7.  8 

relationship  to  timothy  rust 11,16 

avenae,  failure  to  transfer  to  timothj 10 

phlei-pratensis,  name  proposed  for  timothy  rust II.  12,  16,  17 

poculiformis,  name  proposed  for  timothy  rust 11 

JIM  |!l 


20  TIMOTHY   RUST   IN    THE    UNITED   STATES. 

Page. 

Rust,  breeding  for  resistance,  methods 14-17 

timothy,  secidial  stage 10-11, 13, 16 

description 8 

distribution  in  the  United  States 7, 16 

agencies 13-14, 17 

identity  in  the  United  States  and  Europe 9-10, 16 

nomenclature 11-12, 16-17 

relationship  and  physiological  specialization 8-10, 11 

resemblance  to  Puccinia  graminis 8, 10, 11, 16 

winter  survival 12-13, 17 

Secale  cereale,  host  of  timothy  rust 9 

Seymour,  A.  B.,  and  Farlow,  W.  G.,  on  the  rust  of  timothy 7 

Summary  of  bulletin 16-17 

Timothy,  unaffected  by  barberry  rust 10 

varieties,  resistance  to  rust 14-16 

See  Rust,  timothy. 

Trelease,  William,  on  the  rust  of  timothy 7 

Triticum  vulgare,  host  of  timothy  rust 9, 10 

Uredo  graminis,  comparison  with  timothy  rust 11 

Uredospores,  measurements  of  timothy  rust 8 

Wilson,  J.,  Curtis,  C.  F.,  and  Kent,  D.  A.,  on  the  occurrence  of  timothy  rust. .  7 

Wind,  agency  in  the  dissemination  of  rust  spores 13, 17 

224 

o 


UNIVERSITY  OF  FLORIDA 


3  1262  08928  3377 


